8 U. Ss. P. R. R. EXP. AND SURVEYS—ZOOLOGY—GENERAL REPORT. 
List of specimens. 
Locality. When collected. Whence obtained. Collected by— 
Catalogue No. 
5166 | Mouth of Vermilion river, Upper 
IMiscourimesee eee eae nae eee October 25, 1856-| Lieut. G. K. Warren---..----- Driv V- Hayden) —--===- 
FALCO NIGRICEPS, Cassin. 
Falco nigriceps, Cassin, B. of Cal. and Texas I, p. 87. (1853.)—Is. in Gilliss’ U.S. Astron. Exped. II, 1855 
pl. xiv. 
Resembling the preceding, but smaller and with the bill disproportionately weaker. .4dult.—Frontal band white, narrow 
Head and neck above black tinged with cinereous ; other upper parts bluish cinereous, with transverse bands of brownish 
black. Quills brownish black ; tail bluish cinereous, with transverse bands of black. Under parts reddish white, with circula | 
spots and transverse bands of black. Cheeks with a large space of black. 
Younger.—Upper plumage dark brown; tail above brown, barred wi rufous on the inner webs of the feathers. Under part 
Aull reddish yellow, paler on the throat, and with broad longitudinal _tripes of black; flanks and under wing coverts with 
transverse bars and circular spots of reddish white. Bill bluish, legs and toes yellow. 
Total length 15 to 17 inches, wing 11 to 12, tail 6 to 614 inches. 
Hab. Western North and South America. Specimens in National Museum, Washington, and Museum Academy’ 
Philadelphia. 
Like its relative of the eastern States of the Union, /”. anatwm, this species does not appear 
to be abundant on the western coast; or if so, like its eastern congener, it is not easily obtained. 
Three specimens only are in the collections made by the expeditions. 
This is one of the rather numerous species which bear more or less intimate relationship to 
the Falco peregrinus of the old world, and to Falco anatum of the United States. It is 
uniformly smaller than both, though most resembling the former, especially specimens from 
Asia. This bird is as yet known only as an inhabitant of the western countries of the continent 
of America from Oregon to Chie. 
List of specimens. 
Measurements. 
Locality. When collected. Whence obtained. Collected by— 
| Catalogue number. 
| Original number. 
Point of bill to end 
of tail 
Between tips of out- 
stretched wings 
Puget’s Sound, W. T. -- --| Sept. 26, 1854_| Dr. Suckley.------------ 183 | Geo. Gibbs ---| 16.50 | 39.00 
8501 Shoalwater Bay, W. T ----| Mar. 21, 1854_| Governor Stevens-- ------ 63 | Dr. Cooper Sc 17.50 
8500 | © | Bodega, California----.--- Jan,, 1855_---| Lieut. Trowbridge ---.--- 225.2 ALI Szabosea| Sess ees4| Seeeee 
Oy | Sex and age. 
eoee _ al @hile o-- seeeeeee es an on se seeees ee sees -s|MbleutsGillissie2o-- <5 224) 220 tS ees een tal ae 
